Monitoring the Freshness Level of Beef Using Nanocomposite Gas Sensors in Electronic nose

In this paper, an electronic nose comprising an array of polymer and functionalized single-walled carbon nanotube composite gas sensors was developed for monitoring the freshness level of beef in order to prevent people from consuming unhealthy meat. The three types of nanocomposite sensors were tested with various volatile organic compounds in static system. The sensors show a good response to ammonia produced mainly from the beef spoilage. Accordingly it is suitable for detecting the spoilage of beef. The results reveal that nanocomposite gas sensors made of polyaniline (PANI)/ SWNTs-COOH show the highest sensitivity to ammonia. The raw beef was prepared into pieces and kept at room temperature for 5 days. The beef samples were monitored with e-nose day after day to know the meat spoilage and the diurnal freshness of beef could be discriminated by using principal component analysis (PCA). In conclusion, this electronic nose system has the potential to be applied in the real detection of freshness level.